External sound cards have the advantage of less electrical interference, but usually the internal ones have external power not coming from the PCIe slot so it isn’t a big problem. Asus left the market leaving you with good old Creative Sound Blaster again. Choose whatever your budget allows, the two upper tier ones just differ in accessories, but that might have changed. And AV receivers the same, I am not the up to date audio guy what is a good deal. Just try to stay >120 dB SNR on sound cards for high end.
The entire gambling lootboxes were massively popularized by Valve, turning Team Fortress 2 from pay2play to predatory gambling.